Dehydration of sample gas prior to analysis by online analyzer
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Dehydration of sample gas before analysis by online analyzers: How to deal with moisture in the sample gas? Methane-rich gases contain carbon dioxide and water, which can severely affect the operation of online analyzers; freezing and blockages occur easily in winter. The operating pressure is 1.2 MPa – how should moisture be dealt with? I seek help from experts to solve this issue
If the sampling pipeline is frozen and blocked, it is recommended to add pre-treatment steps to remove water near the sampling point. The methods for water removal can be determined in consultation with the pre-treatment supplier; there are many possible combinations such as cooling, separation, filtration, adsorption, etc.
This post was last edited by qugd on 2018-1-21 at 15:51. With such low pressure, where would all that water come from? Isn’t this just normal pressure? It’s no different from atmospheric pressure, and the fluctuations in atmospheric pressure are many times greater than this value. Do you know the relationship between mPa, Pa, and MPa?
Is your goal to measure the water that needs to be removed, or is it for anti-freezing purposes? If anti-freezing is a concern, it is recommended to provide insulation and heating for the pipelines during transportation; steam or electricity can be used for this purpose, which will prevent freezing. Also, what detectors do you use? Generally, detectors require the gas to be clean, free of water; can you still perform measurements with water present? Don’t pre-treatment units have moisture separation devices such as cyclones?
And online analyzers are equipped with explosion-proof air conditioning, aren’t they? If it contains water and heating as well, insulate the external pipes properly; if that’s not sufficient, use heat tracing.
Yes, very professional. Generally, adding some heat tracing is sufficient. With such low pressure, the effect of the Joule-Thomson effect should be minimal ； Identify the exact location of the production process, as well as the ambient temperature. When necessary, in addition to insulating the pipelines, it may also be necessary to insulate the enclosures. Generally, the circuit boards of analytical instruments can withstand temperatures down to -20°C at most.
Install a dehydration suspension separator; it’s easy to find and the cost is not high. In winter, consider installing electric heating and insulation, as well as performing regular drainage. If the water volume is high, there is a direct drainage valve at the bottom of the distributor; reducing its opening slightly will suffice
Do you have any recommendations on where I can buy it?
Just make it yourself – add a cyclone separator; if water still gets through, use a dehumidifier